1. Field of the Invention
The present invention pertains to internal combustion engines and lubricating systems thereof. More specifically, the present invention pertains to apparatus and methods for flushing and cleaning components of an internal combustion engine of the type having a removable spin-on oil filter.
2. Description of the Prior Art
Most four cycle, internal combustion engines, particularly those in automobiles, are lubricated by a wet sump system, i.e. the engine's lubricating oil is contained in the engine crankcase (oil pan). In such engines, an oil pump, typically a gear type or a vane type, is provided in the sump for pumping oil from the sump to the oil distribution system for the moving parts of the engine. Typically, the suction side of the oil pump is connected to an oil strainer or screen to prevent particulates from entering the pump and being forced through the oil distribution system. Such particulates are usually in the form of sludge and may be a mixture of road dust, water, carbon, oil, etc. The sludge is generally dark in appearance and gummy in consistency. If an engine does not run frequently, sludge may be hardened, difficult to dissolve and remove, even if oil is changed frequently. The sludge may accumulate restricting oil flow to the moving parts of the engine. Of course restricted oil flow may result in damage to the engine parts.
To assist in further filtering of oil distributed to an engine, most engines are provided with some type of filter system. Early filter systems were of the "bypass" or "part-flow" type. In a bypass system, oil, after flowing through the oil strainer, is forced under pressure by the oil pump to the gallery or main oil distribution system. Approximately 90% of the oil is pumped directly to engine bearings and other moving parts before it drains back to the oil pan. Only 10% of the oil is diverted into a filter housing where it is cleaned by a filter cartridge before being returned to the sump. Thus, a bypass filter filters only 10% of the oil on a complete circulation cycle.
In the 1950's a better oil filtration system, called the "full-flow" filter system was developed. In the full-flow filter system, oil flows through the oil strainer, to catch large particles of contaminant, then is forced under pressure by the oil pump to the oil distribution system. However, before being distributed to engine parts, all of the oil must pass through the full-flow filter element. Since the filter element could become "plugged" with contaminants, preventing sufficient flow of oil to the engine, a relief or bypass valve may be provided in the filter system to provide normal flow of oil, even though unfiltered, to the engine. The typical full-flow filter element is a "spin-on" type which may be easily removed and replaced with a clean filter on a regular maintenance schedule.
Obviously, the oil strainer through which oil is drawn into the oil pump is critical to the lubrication system of an internal combustion engine. If the oil strainer becomes clogged, particularly after many hours of operation, the flow of oil to the oil distribution system of an engine may be severely restricted resulting in unnecessary wear and eventual failure of an engine. Keeping the crankcase and oil strainer clean would obviously prolong the life of an engine and the automobiles in which they are installed.
In the past, several methods have been devised to clean the crankcase, sump area and oil screen. In one method, used oil is drained, a cleaning agent, such as a lightweight oil or paraffin oil, is placed in the sump and the engine is operated long enough to warm and circulate the cleaning oils through the engine. Then the cleaning agent is removed and the engine refilled with the proper grade oil. This method is frowned on by engine manufacturers and flushes only a small percentage of the contaminants and sludge. In another method, the used oil is drained, the oil pan removed, the crankcase cleaned, the oil screen cleaned or replaced and the engine refilled with clean oil. Obviously, this method is fairly effective however it is relatively expensive and not conducive to ordinary day to day maintenance.
Obviously, better methods of cleaning and flushing the crankcase of an engine have been sought. In U.S. Pat. No. 4,174,231 the crankcase is drained and the spin-on oil filter is removed and replaced with an adapter which is hollow. The crank case is filled with a cleaning and flushing fluid and the engine operated to circulate the fluid through the engine and through the filter fitting and adapter without filtration. The crankcase is then drained, the adapter removed and replaced with a clean oil filter cartridge. Obviously, this forces cleaning fluid and contaminants entrained therewith through the lubricating system of the engine and while it may somewhat clean the crankcase and oil strainer, there is the potential of substantial damage to the engine from contaminants forced through the moving parts.
In U.S. Pat. No. 4,854,277 a blocking device is placed on the upper end of a spin-on oil filter preventing flow of fluid from the oil pump through the filter. Spent oil is drained from the crankcase, flushing fluid is placed therein and the engine operated causing the flushing fluid to pass to the filter cartridge. However, since the filter cartridge is blocked, the internal filter bypass valve opens so that the flushing liquid bypasses the filter cartridge and circulates through the engine. The crankcase is then drained of flushing liquid and a new filter cartridge put in place. This method has the same problems associated with the method of U.S. Pat. No. 4,174,231.
A high speed oil change and/or flushing method in which an additional filter element is required is shown in U.S. Pat. No's 5,044,334 and 5,209,198. These methods require additional filter apparatus and like in the previously described patents, force cleaning fluids directly to the lubrication distribution system of an engine.
Due to the high cost of purchasing and operating today's automobiles, most vehicle owners desire longer life and more trouble-free operation of their vehicles. They also want to avoid costly repairs thereto. For these reasons, owners and operators of internal combustion engines should gratefully receive new methods and apparatus for flushing and cleaning the oil strainer and crankcase of an internal combustion engine to prolong its life and reduce the cost of maintenance thereof.